Landfill Gas
Landfill Gas is generated through the microbial degradation of organic rich materials containing carbon. In an aerobic state (oxygen-rich) the carbon compounds are enzymatically oxidized to produce carbon dioxide, water and energy. In cases where the oxygen is not replenished the carbon dioxide produced will replace the oxygen resulting in an anaerobic (oxygen-depleted) environment. Under these conditions decomposition is undertaken at a slower rate by organisms that favour anaerobic conditions. Under these conditions initially both carbon dioxide and methane gas is produced and latterly just methane gas.
Due to the nature of materials interred at landfill sites this process is prevalent, although these gases may be generated by other below-ground strata such as:-
- Buried made ground/fill containing organic or biodegradable material
- Saturated soils with a high organic content such as peat
- Compacted organic rich subsoils or buried topsoil
- Geological strata such as coal measures
Gas, generated at sites where such materials are present may, dependent upon the situation, migrate laterally, exposing adjacent sites to potential risks from the presence of these gases.
A programme of gas monitoring can identify the potential risks that may be present at or adjacent to such sites.